Door latch tripping mechanism



July 14, 1953 H. w. SANFORD DOOR LATCH TRIPPING MECHANISM 5 Sheets-Sheet 1 Filed April 16, 1945 -LILTI IFf y 4, 1953 H. w. SANFORD 2,645,368

DOOR LATCH TRIPPING MECHANISM Filed April 16, 1945 5 Sheets-Sheet 3 Hill" "HHHHH July 14, 1953 H. w. SANFORD DOOR LATCH TRIPPING MECHANISM 5 Sheets- 511a 3 Filed April 16, 1945 July 14, 1953 H. w. SANFORD 2,645,368

DOOR LATCH TRIPPING uscmnxsu Filed April 16, 1945 5 Sheets-Sheet 4 y 1953 H. w. SANFORD 2,645,363

DOOR LATCH TRIPPING MECHANISM Filed April 16, 1945 5 Sheets-Sheet 5 Patented July 14, 1953 DOOR LATCH TRIPPING MECHANISM Hugh W. Sanford, Knoxville, Tenn., assignor to The Sanford Investment Company, Wilmington, Del., a corporation of Delaware Application April 16, 1945, Serial No. 588,577

This invention relates to improvements in door latch mechanisms, particularly for mine cars and other conveying devices having drop bottom doors for discharge of the lading therefrom. a

This application is a continuation-in-part of my prior applications, Ser. No. 432,341, filed February 25, 1942, (now Patent No. 2,399,708, granted May 7, 1946), and Ser. No. 571,170, filed January 3, 1945.

In the door latch mechanisms set forth in my prior applications, the latch or latches that support the free edge of the door were adapted to be engaged from beneath the car by tripping mechanism mountedat the trackway and timed to be operated in synchronism with the movement of the car or vehicle along the trackway, whereby a tripping member would be moved into engagement with the latch hook for movement of the hook with respect to the car to a released position, thereby unlatching the door for dropping movement. The character of the engaging face of the latch hook at the point of engagement thereof with the tripping arm was downwardly inclined toward the rearward end of the car. tripping member during movement of the car there-over unless held up in engagement with the hook by'relatively strong pressure.

One object of this invention is to improve the character of the latch mechanism and its coacting tripping mechanism so there will be no tendency to deflect the tripping member by pressure bearing relation of the latch therewith during passage of the car over the tripping mechanism. On the other hand, the character of the latch hook, and its coacting tripping member, is such that the tripping member will tend to be moved upward with respect to the hook, rather than downward, prior to the time when the hook starts to retract from its supporting engagement with the door. This provides a positive connection between the unlatching member and the hook and permits the unlatching member to be held up in its elevated position by a relatively light pressure during the period of unlatching, and yet the hook will be released positively from its latched position, There will be no tendency for the latch hook to slip off the tripping member during the period that the hook is moving backward from its latched to its unlatched position.

In the type of latch. tripping mechanism set forth in my prior applications referred to above in which a tripping arm projects upwardly in a rearward direction relative to the car for un- 17 Claims. (Cl. 214-58) This would have a tendency to deflect the latching, the lowering movement of this tripping arm after releasing the latch, is toward the end sill structure and out-from beneath the rearward door.

Another object of this invention is to improve the action of the tripping arm, so as to allow it to fall away from, rather than toward, the end sill structure, and whereby it will be located entirely rearward of the door as thecar passes over the tripping mechanism, so as to be out of the way of the door and not to interfere with the opening movement of the latter. This allows more time and allows less clearance to free the tripping arm from the hook, and to allow the former to be depressed so as to pass beneath the bumper structure.

These objects are accomplished, according to thepreierred embodiment of the invention, by providing an engaging face on the latch, which is preferably the lower face of a notch provided in the front edge of the latch, which engaging face slopes downward and forward of the car in position to be engaged by a tripping member yieldably held in elevated position where it may engage said face during forward movement of the car to press the latch hook rearwardly out of supporting engagement with the door and release the door for dropping. The angle of the slope of the engagin face of the hook is such that the tripping member tends to be pressed upward during the time that the latch hook is moving from a point where it supports the free edge of the door to a pointwhere it releases the door.

A further object of the invention is to provide for the locking of the latch hook against releasing movement whereby to make it impossible for the doors to drop when the car is in transit. This is desirable particularly when workmen are riding in the cars, as may be done occasionally in transporting workmen into and out of the mine.

I have provided a supporting member for the latch hook which is rotatable with the hook in moving to a released position, and has: means for locking this supporting member against turning movement so as to hold the hook against releasing acticn,,whereby the latch hook will be retained in its latched position.

The invention is shown applied to a mine car as the preferred application thereof, in the accompanying drawings in which:

Fig. 1 is a side elevation of the mine car and latch tripping mechanism;

Fig. 2 is a top plan view of the tripping mechamsm;

Fig. 3 is a longitudinal sectional view therethrough including a portion of the car passing thereover;

Fig. 4 is a cross section therethrough on the line 44 of Fig. 3, and showing the coacting portion of the latch mechanism, with the remainder of the car structure broken away and illustrated generally in dotted lines;

Fig.5 is a similar view showing the application of a lowering tension device thereto as a modification;

Fig. 6 is a side elevation thereof;

Fig. '7 is a detailed side elevation of the latch hook lock mechanism;

Fig. 8 is a transverse section therethrough on the line 88 of Fig. 7, showing the lock in its locked position;

Fig. 9 is a similar view showing the lock means in released position; and

Fig. 10 is a detailed cross section through a portion of the latch hook and its suporting shaft.

This invention is shown as applied to a mine car of the general type set forth in my prior patent, No. 2,001,471, granted May 14, 1935, adapted for conveying coal or other loose lading from a receiving point to a tipple or other point of discharge. The mine car is shown to be of the 4-wheel type, having three drop bottom doors interconnected for release in one-two-three order. This application of the invention is used, however, merely for purpose of illustration, and it is evident that the subject-matter of this invention may be applied to other types of cars, vehicles, and drop bottom conveyors in general,

wherever it may be desirable to release bottom doors for dropping, in which the principles of this invention may be applicable.

The general structure of the car illustrated comprises a car body formed of side and endwalls i and 2, rigidly secured together, the side walls I rising froma pair of oppositely disposed side sills 3 (Figs. 1 and 4), connected together at the ends of the car by means .of combined end-sills and bumpers, designated generally at 4. The side and end-sills 3 and 4 comprise the frame structure of the car for supporting the lading body thereof, and between which is a bottomopening designed generally for discharge of the lading therethroug h.

The car is supported upon wheels 6 and axles 1- connected with the sidesills 3. The wheels 6 are adapted to travel on a track formed by a-pair of laterally spaced rails indicated generally at R. a The car is shown of the character provided-with three drop bottom dooors adapted for discharge in one-two-three order from front to rear of the car. These doors are designated respectively by the numerals B, 9 and II]. The forward doors 8 is pivotally supported at its forward edge on a hinge rod l I, while each of the middle and rearward doors 9' and i0 is slidably and pivotally mounted on a hinge rod l2 extending between the frame structures at opposite sides of the drop bottom opening.

The extreme forward edge of each of said doors 9 and I0, when in closed or latched position, projects laterally from the hinge rod l2, and is adapted to support the free edge of the next forward door. Then upon release of the rearward door, it may drop sufficiently to drag and forward door in the bin for discharge of the lading thereon, as soon as room enough is provided in the bin therebeneath. The other doors drop in succession during the continued forward movement of the car over the bin or tripple in one-two-three order from front to rear of the car.

After dumping in passing over the bin or tipple, the doors are adapted to be closed by the usual door-closing rails located in the track. The doors have indentations l3 in the under faces thereof to ride on the door-closing rails,

V which indentations extend transversely of the doors throughout substantial portions of the width thereof. The doors are thus moved successively about their hinge rods to their closed positions, and the middle and rearward doors are pushed forward into wedging relation with the next forward door, adapted to be latched in closed position.

The foregoing car structure, to which this invention is shown applied as hereinafter described, is set forth more in detail in my prior patents, No. 2,001,471, May 14, 1935, and No. 2,036,644, April '7, 1936, to which reference is made for a more complete illustration of the structure there- As shown in Figs. 1, and 3 to 5, provision is made for latching the free edge of the rearward door 10 in closed position, thereby holding the several doors closed, to retain the lading in the car until the latching means is released for dumping. For this purpose, I have provided on the free edge of the rearward door In, one or more supporting trunnions [4, one for each latch of said door. I prefer to use a pair of latches, each designated generally by the numeral I5 and spaced apart as indicated in Fig. 4, symmetrically with respect to the longitudinal center of the car. The latches l5 are pivotally mounted on a, cross shaft I! supported by brackets l8 secured to the adjacent end wall 2 of the car. Each of the latches I5 is preferably so constructed, orspring-pressed, as to be disposed normally in its door supporting position, or to return thereto automatically when disengaged for release of the lading.

Each of the latches I5 is provided with a concave seat l9 (Fig. 3) at the forward face thereof in position to receive the end of the adjacent trunnion I attached to the free edge of the rearward door l0. As shown in Fig. 3, the seat 19 is located on the opposite side of the vertical plane passing through the pivot axis of the latch is from the door l0, so that the weight of the door and the lading thereon tends to maintain the latched relation without any tendency for this weight to push the latch to one side. This is particularly true when the concave seat is engaged by a convex end of the trunnion, whereby any movement. of the latch tending to release the door must raise up the free edge of the door.

Each of the latches I5 is provided preferably with a lateral pin 20 attached thereto and projecting through a slot 2| in the adjacent portion of the end sill 4 (Figs. 3. and 4).

The foregoing structure corresponds generally with that set forth in my prior application for Door Latch Mechanisms, Serial No. 432,341, filed February 25, 1942, now Patent No. 2,399,708, granted May '7, 1946.

As shown in Figs. 3 and 4, the latches [5 are interposed between the free edge of the rearward door l0 and the adjacent end-sill structure 4, underneath a guard plate 23 secured to the adjacent end wall 2. The latches 15- are so con- 5 structed and arranged that they are disposed wholly above the lower edges of the end-sills of the car, and also,-preferably, above the lower face of the rearward door, in protected positions. This prevents disarrangement of the latches or damage thereto in the event of wreckage of the car or from contact with obstructions in the trackway, as might occur in a mine, thus assuring adequate protection of the latches to maintain these in proper operative positions.

Each latch I5 is so mounted in protected position between the door l and the bumper 4 that a tripping space is provided between said door andthe latch I5 in latched position for entry of a tripping arm therebetween.

To accommodate the tripping mechanism hereinafter described, each latch hook has its forward face, beneath the seat l9, provided with a notch 25 therein, having a lower engaging face 26 which slopes downwardly and forwardly relative to the length of the car. This face 26 is adapted to be engaged by the tripping. arm as hereinafter described, and as shown in Figs. 3. and 4, to release the latch hook from supporting engagement with thedoor.

The tripping mechanism for the latches I5 is adapted tobe mounted in the trackway between the opposite rails R at a point adjacent the bin or other place of dumping. Since the latches i5 are laterally displaced symmetrically on opposite sides of the longitudinal vertical plane through the center of the car, a tripping device may be provided for each of the respective'latches. Separate tripping devices should be provided where the latches are pivotally mounted independently on the cross shaft ll, although one tripping device may be used if the latches are secured to said cross shaft, as hereinafter described.

In the form shown in Figs. 2 to 4, the tripping mechanism is mounted preferably on a base 21, shown in the form of a dumping plate securely mounted in suitable position in the trackway, preferably by being secured as shown upon the base flanges of the rails R. Secured to the under side of the dumping plate 2'! are bearing'boxes 28 and 28, the bearing boxes 28 being disposed adjacent opposite edges of the dumping plate 2i, while the bearing box 28 is in axial alignment therewith midway of the width of the plate. These bearing boxes are secured to the dumping plate 21 as by bolts 29.

Shafts 30 extend transversely between the bearing box 28' and each of the bearing boxes 28, and are arranged in axial alignment with each other on respective opposite sides of the center of the tripping device. Theshafts 30 are independent of each other and capable of separate operation to provide forthe independent unlatching of the respective latches, although one shaft may be used for the tripping elements of bothlatches, if they are to be unlatched simultaneously. In that event, only two bearing boxes will be required.

In the form shown, each of the shafts 30 has fixed thereon, as by welding, an upwardly extending arm 3| which is inclined forwardly of the length of the car as illustrated in Fig. 3. The arm 31 supports on its upper forward end thereof a contact member 32, the upper face of which is somewhat wedge-shaped and is adapted to be deflected under the lower face of the car during movement of the latter over the tripping mechanism, so as to deflect this contact member beneath the car. The purpose and function of this contact member are substantially the same as set forth more in detail in my prior application for Latch Tripping Mechanisms, Ser. No. 571,170, filed January 3, 1945.

The opposite end of each shaft has fixed thereon, as by welding, a tripping arm 33 that extends in a forwardly inclined direction relative thereto, substantially parallel with the arm 3|.

The forward upper end of the tripping arm 33 carries an offset bar 34 which has a wedgeshaped upper edge portion 35 in position to enter the notch 25 and engage the face 23 when the contact member 22 is substantially in its uppermost position, as shown in Figs. 3 and 4.

The'contact arm 3! and tripping arm 33 are arranged to extend upwardly through the dumping plate 21 which is slotted at 36 and 3'1, respectively, to accommodate these arms as shown in Fig. 2, for freedom of upward and lowering movement thereof. The arms are so mounted on each shaft 33 in side-by-side relation as to dispose the contact member 32 and tripping member 34 adjacent each other, asshown in Fig. 4, with the tripping member in position to engage and aclimit arm 38 is shown as disposed intermediate the tripping arm 33 and the bearing box 28. This a limit arm 38 is adapted to regulate the upward and downward movement of the contact and tripping arms.

Welded or otherwise secured to one side of the limit arm 33 adjacent the forward end thereof is an abutment 39 in position to engage the lower end of a limit screw 40. This screw 40 is threaded through the dumping plate 21 and through a threaded bar ll fixed to the under side thereof,

as shown in Fig. 3. This limit screw 40 may be adjusted up and down with respect to the dumping plate 21 and locked in its adjusted position by a jambnut 42. When properly adjusted, the limit screw 40 will be in position to engage the abutment 39, so as to limit the upward swinging movement of the limit arm 38, and thereby limit the upward movement of the contact member 32 and tripping member 34.

These parts are held yieldably in elevated positions by a coiled spring 43 which is sleeved over a bolt M that is suspended from the dumping plate 21, as shown in Fig. 3. The bolt 44 extends loosely through a spring seat 45 fixed to a side of the limit arm 38. The coiled compression spring 43 has one end thereof seated against the under side of. the seat 45 while the opposite end of said spring is confined by a washer 46 held by nuts 4? threaded on the lower end of the bolt M, The tension or the spring may be varied by adjusting the nuts ti, but the compression. of the spring should be sufficient to hold th tripping mechanism in its elevated position normally until depressed by the passage of the car or other conveyance thereover, whereby the contact and tripping elements will be deflected under the bottom structure of the car or conveyance to operative positions as shown in Fig. 3.

This action will position the tripping edge 35, so as to cause engagement thereof with the downwardly and forwardly inclinedface 26 of the latch hook as the car passes over the tripping mecha- 7 nism; and thereby will qmovethe latch hook from I At the same (time, this forward movement of the car will cause the deflection of thecontactmember 3 2 and tripping edge 35 as will be evident from Fig. 3 to allow the bumper to pass thereover Without obstructing such forward movement.

As the tri ping edge 35 engages the face 26 cf the latch hook during the-forward movement of the car over the tripping mechanism, and swings the latch hook to its released position, the angle of the face 26 changes with respect-to the angle of the tripping arm 33, while said arm 33 remains substantially in the same position. During this movement, the downward inclination of the face 26 forwardly of the'ca r will tend to push upward on the tripping edge 35 to insure the maintenance of engagement ofthis tripping edge-with the face 26 throughout the time that the latch IE is-being moved to its released position. Thus there is no tendency for the tripping edge to slip off the latch hook, but any tendency of relative movement between these edges is-upward rather than downward, to increase the holding action of the tripping member on the latch until the latter is moved to-its released position. Through the entire movement :of the hook, the co-efiicient of friction between the tripping edg and the latch is suflicient to prevent the latch from slipping off the hook aagainstthe'action of the spring iS whichistendingto hold the tripping edge 35 as high as it is :lperr'nitted to go by the adjustable limit screw 45!; Thus the latch is effectively released withoutany danger that the tripping memberwill be deflected without releasing the latch.

While I have shown two separate tripping de vices'for'the-respective latches spacedon opposite sides of the longitudinal center of the car and prefer'to-use such separate devices, a single tripping-device inay=be usedif the latches are fixed to the cross-shaft I 7. Generally, however, it is preferred to use separate trippingdevices for the espective latches.

When the conditions of operation are such that the rear end of the car may be caused to sine sideways, so that it may be possible for on tripping to release its latch before the other has unlatched its latch, the respective latches should be mountedindependently for relative movement on the cross shaft ll, rather than fixed thereon. When this is soprovided, each latch will be released independently and regardless of the way the car is slued, and regardless also of any variation in thelength of the respective tripping arms or in the set-up of the mechanism.

It is desirable that provision be made for lowering th tripping mechanism manually either for the passage of .cars thereover without dumping or in a rearward direction, or for the passage of a locomotive-or otherconveying device that may not be accommodated to the tripping mechanism.

I haveprovided accordingly for the manual lowering of the tripping mechanism when desired.

Accordingly, each of the shafts 30 has a depending arm'48, as shown in Figs. 3 and 4, connected by a chain 49 with a corresponding depending arm I50, suspended from a roller bar 5|. The roller bar 5| extends transversely of the dumping plate 2'! and is mounted thereon in 7 eye members 52 in which it is journaled. One

end of the bar .5! is provided with a hand lever 52 fixed thereon. Upon swinging movement of the hand lever 52' in the direction shown by the arrow in Fig. 3, the tripping arms will be lowered out of position for engagement with cars passing thereover, so that the cars will not trip, or to avoid interference with other conveyances movable along the trackway for .nondumpingoperation.

In the formdescribed above, the compression spring 4-3 is used to hold the tripping mechanism in its operating position. I have found, however, that under some circumstances, it may be preferable to use a'tension spring, rather than acompression spring, for this purpose, as shown in Figs. 5 and v6. Accordingly, the limit arm 38 that extends outwardly from the supporting shaft serves merely .to limit the upward movement of the tripping mechanism. The depending arm 48" is preferably extended beyond that of the arm 48 in Fig. .3 to provide greater leverage, and the lower end thereof is attached to one endofa tension spring -43 constructed under proper tension. The opposite end of the spring 43' is connected by an'eye-bolt 44' with a depending bracket 15 suspended from the dumping plate 2-1. Separate tension springs 3' are provided for the respective shafts 36', as shown in Fig. 5.

.I have found that a long tension spring, as shown, does not tend to buckle as does a long compression spring, so that better spring action may :be obtained under some circumstances.

Furthermore, the tension spring tends to .maintain better-control of the tripping mechanism in its elevating movements, so that the arms do not tend to bounce as much when using tension springs as has been encountered in some circumstances'in the use of compression springs. Accordingly, tension springs may be used in this manner if desired.

It maybe desirable under some circumstances to release the latches manuall-yto open the bottom doors and dump the lading, as when the car is standing still on the trackway. This may be done by extending the latchsupporting shaft throughone of the side flare plates of the car body to a point externally thereof as shown for instance in Fig. 8. The shaft 17' that supports the latches is preferably round between the side wall flare plates l, but at least oneend of this shaft I l is preferably extended through the flare plate .I to a point externally of the confines of the car body. At this point, the shaft extends as square in cross section, as indicated at 54,

although the shape thereof may be any desired form. This squared end is adapted to receive an ordinary hand crank .or other tool which may be applied thereto forrotating the shaft H in counter-clockwise direction to cause manual release of the'latches l5'when this may be desired.

Thus the door may be unlatched manually withand through the cross-shaft 11 to secure each of the latch hooks to the shaft. Then, in order to release both hooks by rotation of a single shaft, the rotation of the shaft must continue to take place to an extent sufficient to take up this lost motion provided by the slots 55 and continue to an extent where both hooks will be released and unlatched simultaneously.

It is often desirable to lock the latch mechanism against accidental release, especially when workmen are riding in the car, for which purpose I have provided a locking device as shown in Figs. 7, 8 and 9. This is used in connection with the squared end 54 of the cross-shaft ll at a point externally of the side flare plate I, and the locking device is preferably supported by the flare plate.

In the form shown, the locking device is carried by a bracket 57 welded or otherwise rigidly fixed to the outer face of the flare plate and having a stub shaft 58 journaled therein. One end of the stub shaft 58 has fixed thereto a looking member 59 disposed on one side of the bracket 51 in position to be turned up between the bracket and the adjacent face of the squared end 54 of the shaft IT to hold the shaft against turning movement. The opposite end of the stub shaft 58 has fixed thereto a crank member fill carrying a handle 6| thereon for manual shifting of the locking member 59. This crank fill should be considerably heavier than the locking member 59, so that normally it will tend to rotate downward to the position shown in Fig. 8, holding the locking member in its locking position. The parts are thus disposed when the car is in transit and it is not desired to actuate the latches for release of the doors.

When the car gets to the dumping bin, or it is desired to release the locking means, it is necessary merely to rotate the crank 60 to the posi tion shown in Fig. 9, where it will be supported by a stop 62, thus holding the locking member 59 out of engagement withthe squared end 54 of the cross-shaft IT. This will leave the shaft free for turning, movement by the tripping mechanism, allowing the dumping of the lading automatically in the manner described above. It will be evident that the locking mechanism may be used when desired and yet it may be retained in'inoperative position when not required, allowing dumping of the car automatically.

The locking mechanism and squared end of the shaft may be protected by an extended portion 63 on the bumper structure, shown in Fig. 8, against injury thereto.

I claim:

1. In conveying mechanism, including a dump ing conveyance having a drop bottom door and mounted on a trackway for movement therealong, said door being mounted for downward swinging movement about an axis extending transversely of the conveyance, the combination of a latch mounted on the conveyance for movement in a direction lengthwise of the conveyance and having means for engaging an edge portion of the door for supporting said door and movable relative thereto to release the door for dropping, said latch having a downwardly and forwardly inclined face below said engaging means, and a tripping member mounted in the trackway in position for upward movement relative thereto to a tripping position, said tripping member having a hook portion thereon in position for engaging the downwardly and forwardly inclined face of the latch when said member is in engaging position to cause movement of the latch to release the door for dropping.

2. In conveying mechanism including a drop bottom mine car mounted on a trackway for movement therealong, said car including a lading body having a drop bottom door hinged for downward swinging movement about an axis extending transversely of the car, the combination of a latch hook having a seat therein in position to engage the rear edge portion of the door to support said door in latched position, said latch hook having a notch in the forward edge thereof below the seat with a downwardly and forwardly inclined lower face at a side of the notch, a tripping device mounted in the trackway and having a hook portion in position to engage said downwardly and forwardly inclined face upon forward movement of the conveyance relative to the track,- way to move the latch to release the door for dropping.

3.In conveying mechanism including a drop bottom mine car mounted on a trackway for movement therealong, said car including a lading body having a drop bottom door hinged for downward swinging movement about an axis extending transversely of the car, the combination of a latch hook having a seat therein in position to engage the rear edge portion of the door to support said door in latched position, said latch hook having a notch in the forward edge thereof below the seat with a downwardly and forwardly inclined lower face at a side of the notch, a tripping device mounted in the trackway and having a portion in position to engage saiddownwardly and forwardly inclined face upon forward movement of the conveyance relative to the trackway to move the latchto release thedoor for'dropping, said portion of the tripping device being substantially hook-shaped to engage said face of the latch hook a sufficient length of time for release of the hook from the door, and means for moving the tripping device to engaging position in timed relation with the movement of the car along the trackway.

4. In tripping mechanism adapted to be mounted at a trackway to release a drop bottom door latch, a support, a tripping arm mounted on the support for upward movement, and means forming a substantially hook-shaped latch-engaging portion on the upper end of said tripping arm and extending at an acute angle to the lower end portion of the tripping armin position to engage the latch and to 'move the latch to a re-- leased position.

5. In tripping mechanism adapted to be mounted at a trackway to release a drop bottom door latch, a support, a tripping arm pivotally mounted on the support for upward swinging movement, and a latch-engaging member fixed to the upper end of said tripping arm and extendin laterally therefrom at an acute angle to the lengthof said arm therebelow in position to engage and release the latch.

6. In tripping mechanism adapted to be.

mounted at a trackway to release-a "drop bottomdoor latch, a support, a shaft journaled on the support, a tripping arm carried by the shaft and adapted to extend upward therefrom forreleasing the latch, resilient means tending to move said tripping arm to its upper tripping position, a depending arm carried by the shaft, a second depending arm pivotally mounted on the support, flexible means connectin said depending arms together, and manually actuated means connected with the second-mentioned depending arm for manually lowering the tripping arm.

7. In tripping mechanism adapted to be mounted at a trackway to release a drop bottom door latch, a support, a shaft journaled on the support, a tripping arm .carried by the shaft and adapted to extend upward therefromfor releasing the latch, resilient means tending to move said tripping arm to its upper tripping position, a

"depending arm carried by the shaft, a second depending armpivotally mounted on the support,

'flexible means connecting said depending arms together, and manually actuated mean .con-

nected with the second-mentioned depending arm for manually lowering the tripping arm, said and a hook-shaped projection on the upper portion of the tripping arm extending laterally from the arm at an acute angle to the lower end portion of said arm, said projection being arranged to engage and release the latch.

9. In tripping mechanism adapted to be mounted at a trackway for movement of a conveyance along the :trackway to release a drop bottom door latch on the conveyance, a support adapted to be mounted in the trackway, a tripping arm mounted on the supportfor upward movement to a tripping position, means yieldably urging said tripping arm upwardly to the tripping position, and a hook-shaped latch-releasing projection on the upper end portion of the tripping arm for actuating the latch to release the door.

10. In tripping 'mechanism adapted to be mounted at a trackway for movement of -a conveyance along the trackway to release a drop bottom door latch on the conveyance, a support adapted to be mounted in the trackway, a tripping arm mounted on the support for upwardmovement to a tripping position, means yieldably urging said tripping arm upwardly to the tripping position, a hook-shaped latch-releasing projection on the upper end portion of the tripping arm for actuating the latch to release the door, said projection extending laterally from the arm at an acute angle to the lower end portion of said arm.

11. In tripping mechanism adapted to be mounted. at a 'trackway for movement of a conveyance along the trackway to release a drop bottom door latch on the "conveyance, a support adapted to be mounted in the trackway, a trip-- ping arm mounted on the support for upward movement to a tripping position, means yieldably urging said tripping arm upwardly to the tripping position, a hook-shaped latch-releasing projection on the upper end portion of the tripping arm for actuating the latch to release the door, said arm mounting means being constructed for down- 12 ward swinging movement of the tripping arm out of tripping position in a direction forwardly of the movement of the conveyance along the trackway.

12. In latch tripping mechanism adapted to be mounted at a trackway to release a drop bottom door latch of a conveyance traveling lengthwise of the trackway, a support, a tripping arm having a hook on the upper end portion thereof in position to release the latch as the conveyance passes over-the traokway, and means for pivotally mounting the arm on the support normally in a arm on the support normally in an upwardly inclined position in the direction of forward movement of the conveyance on the traclrway, yieldable means normally urging said arm in an upward direction, and a hook carried by the upper portion of the arm for actuating the latch during movement of the conveyance thereover.

14. In conveying mechanism, including a dumping conveyance having a drop bottom door and mounted on a trackway for movement therealong, said door being mounted for downward swinging movement to release the lading, the combination of a latch mounted on the conveyance for movement in a direction lengthwise of the conveyance and having means for engaging an edge portion of the door for supporting said door and movable relative thereto to release the door for dropping, latch release means connected with the latch, a tripping arm, and means pivotally mounting sa'id arm in the trackway in an upwardly inclined position toward the front of the conveyance passing over the trackway and having a hook on the upper end portion thereof for actuating the latch release means.

15. In conveying mechanism, including a dumping conveyance having a drop bottom door and mounted on a trackway for movement therealong, said door being mounted for downward swinging movement to release the lading, the combination of a latch mounted on the conveyance for movement in a direction lengthwise of the conveyance and having means for engaging an edge portion of the door for supporting said door and movable relative thereto to release the door for dropping, latch release means connected with the latch, a tripping arm extending lengthwise of the trackway, a pivotal support for said arm mounted in the trackway, a pivotal support for said arm mounted in the trackway and disposed rearwardly thereof relative to the direction of movement of the conveyance on the trackway, and a hook on the forward portion of said arm for engaging and actuating the latch release means during movement of the conveyance thereover.

16. In conveying mechanism, including a dumping conveyance having a drop bottom door and mounted on a trackway for movement therealong, said door being mounted for downward swinging movement to release the lading, the combination of a latch mounted on the conveyance for movement in a direction lengthwise of the conveyance and having means for engaging an edge portion of the door for supporting said door and movabl relative thereto to release the door for dropping, latch release means connected with the latch, a tripping arm extending substantially lengthwise of the traokwayand having a hook on the forward end portion thereof in position for engaging and actuating the latch release means during movement of the conveyance thereover, means pivotally mounting the rearward end portion of the arm in the traokway for downward swinging movement relative thereto, and means yieldably urging the arm in an upward direction to a tripping position.

17. In conveying mechanism including a drop bottom conveyance adapted to be mounted on a trackway for movement therealong, said conveyance including a lading body having a drop bottom door hinged for downward swinging movement about an axis extending transversely of the conveyance, the combination of a latch in position to hold thefree edge portion of the door in closed position, actuating means connected with the latch for moving the latch to a released position, said actuating means having a notch in the forward edge portion thereof, and a tripping device mounted in the trackway and having a hook portion in position to engage in said notch upon forward movement of the conveyance relative to the trackway to move the latch to released position.

HUGH W. SANFORD.

References Cited in the file of this patent UNITED STATES PATENTS Number 5 387,241 867,166 1,212,629 1,434,939 1,584,415 10 1,634,225 1,658,584 1,727,689 1,796,348 1,803,384

Number Name Date McCaslin Aug. 7, 1888 Smith Sept. 24, 1907 Greenawalt 1 Jan. 16, 1917 Wilkes 1- Nov. 7, 1922 Wine May 11, 1926 Wine June 28, 1927 Wine Feb. 7, 1928 Almquist Sept. 10, 1929 Sanford Mar. 17, 1931 Dietrichson May 5, 1931 Griflith Nov. 29, 1932 Jones Apr. 11, 1933 Getaz May 9, 1933 Rose Dec. 17, 1940 Sanford May 7, 1946 Kepner Nov. 8, 1949 FOREIGN PATENTS Country Date Switzerland Dec. 11, 1924 Great Britain May 5, 1930 

